Water-soluble shotshell wad and method of manufacturing same

ABSTRACT

A shotshell wad is molded from a water-soluble plastic such as an ethylene oxide polymer or a poly(ethylene oxide)-urea blend. A water-insoluble layer is formed on the wad either by coating the wad with a water-soluble material or exposing the outer surface of the wad to a material such as an acrylic acid polymer which reacts with the surface of the wad to produce a water-insoluble association compound covering the surface so that the wad is insoluble while in the shotshell. When the shotshell is fired, this water-insoluble layer is abraded and burned so that a substantial portion of the water-soluble material is exposed placing the wad in a water-soluble condition.

ilited tates Curran Aug.6,1974

[75] Inventor: Roger J. Curran, Stratford, Conn. [73] Assignee: Remington Arms Company Inc.,

Bridgeport, Conn.

[22] Filed: Dec. 13, 1972 {21] Appl. No.: 314,708

[52] US. Cl. 102/95, 102/42 R [51] Int. Cl. F421) 7/08 [58] Field of Search 102/42 R, 42 C, 95, 44,

102/43; 117/132 R, 132 C, 138.8 R, 138.8 E

{56] References Cited UNITED STATES PATENTS 1,872,107 8/1932 Bond 102/95 2,628,560 2/1953 Randall 102/95 X 3,157,121 11/1964 Daubenspeck et a1. 102/44 X 3,229,639 1/1966 Moehlmann et a1. 102/42 R INSOLUBLE Primary Examiner-Robert F. Stahl Attorney, Agent, or Firm-John H. Lewis, Jr.; Nicholas Skovran; Joel D. Talcott 5 7] ABSTRACT A shotshell wad is molded from a water-soluble plastic such as an ethylene oxide polymer or a poly(cthylenc oxide)-urea blend. A water-insoluble layer is formed on the wad either by coating the wad with a watersoluble material or exposing the outer surface of the wad to a material such as an acrylic acid polymer which reacts with the surface of the wad to produce a water-insoluble association compound covering the surface so that the wad is insoluble while in the shotshell. When the shotshell is fired, this water-insoluble layer is abraded and burned so that a substantial portion of the water-soluble material is exposed placing the wad in a water-soluble condition.

15 Claims, 1 Drawing Figure SOLUBLE WATER-SOLUBLE SHOTSHELL WAD AND METHOD OF MANUFACTURING SAME This invention relates to shotshell wads and more particularly to a shotshell wad which is water insoluble while in a shotshell and is rendered water soluble only after the shotshell has been fired.

For some time now shotshell wads have been manufactured from various plastic compositions which are easily molded and make possible wad configurations providing greatly improved patterns and shotshell ballistics. The use of these plastic wads, however, may tend to contribute to our present ecological difficulties inasmuch as the materials used are, to a great extent, indestructible and thus difficult to dispose of. Further, when fired over lakes or ponds, as for the hunting of waterfowl, the wads land on the water and, being generally less dense than water, float on the surface causing a rather unsightly condition.

It has long been desired to find a manner of producing a disposable wad. However, proposed solutions to the problem have themselves presented further problems, heretofore unsolved. If a wad is manufactured which will degrade or dissolve as a result of the effects of natural forces, it will also dissolve or degrade within the shotshell if those natural forces are present. For example, a desirable solution to the wad disposal problem is to produce a water-soluble shotshell wad. Such a wad would be most desirable in applications such as waterfowl shooting where it will be fired over water. However, waterfowl hunters tend to expose their shotshells to much water penetration, such as by storing them at the bottom of a blind or boat. Water leaking into the shotshell would dissolve the wad prior to firing so that the entire usefulness of the shotshell would be defeated.

In accordance with this invention, a shotshell wad is molded from a water-soluble plastic and provided with a water insoluble coating which protects the wad from water while in the shotshell. The coating has sufficient thickness to permit the handling and light abrasion generally present during shotshell loading and yet is sufficiently thin to permit the coating to be substantially destroyed when the shotshell is fired.

It is an object of this invention to provide a shotshell wad which is disposable by natural forces.

It is another object of this invention to provide a shotshell wad which is disposable by natural forces and yet protected prior to firing.

It is still another object of this invention to provide a shotshell wad formed of water-soluble material and having a water-insoluble coating which is destroyed during firing.

It is a further object of this invention to provide a method of manufacturing a shotshell wad which is insoluble while in a shotshell and soluble after the shotshell has been fired.

These and other objects and advantages of this invention will be readily apparent when the following specification is read in conjunction with the appended drawing which is a fragmentary cross-sectional view of a shotshell wad made in accordance with this invention.

The method of this invention generally comprises the steps of molding a shotshell wad from a water-soluble material and forming a water-insoluble coating on the surface of the shotshell wad either by coating the surface with the insoluble material or by causing the surface to react chemically to form a water-insoluble complex thereon.

The shotshell wad as referred to herein may be of any desired configuration as is well known to those skilled in the art and may include a shot containing portion, a cushion and an obturating seal. If desired, a wall of the shot containing portion may be slit to form petals in a well known manner.

The shotshell wad is molded of a suitable soluble material such as an ethylene oxide polymer. If desird, the poly (ethylene oxide) may be blended with an equal quantity of urea to produce a material having a higher melting point. Of course, the wad may be constructed of other soluble substances or combinations of materials exhibiting desirable physical characteristics without departing from the spirit and scope of this invention. Shotshell wads molded of such materials have been successfully fired even with loads of steel shot particles.

Although a shotshell wad molded of a poly(ethylene oxide) blend is suitable for use in a shotshell, it may be highly unsuitable for extended storage inasmuch as water seeping into the shotshell or even high humidity in a storage area may cause significant deterioration of the wad due to the high degree of solubility of poly- (ethylene oxide). Shotshell wads molded of a blend of poly(ethylene oxide) and urea have been completely dissolved in uncirculated water at room temperature in less than one day and cannot be identified as wads after only a few hours.

Therefore, in accordance with this invention, an insoluble layer is provided on the entire outer surface of the wad. This layer may be produced by various means such as by coating the wad, either by spraying or immersion, with an adhering water-insoluble material or by spraying or immersing the wad in a material which will react with the soluble material to chemically produce the water-insoluble layer.

A preferred water-insoluble adhering material is poly (vinylidene chloride) which is preferably dissolved in a balanced solvent, i.e. one that will dissolve poly(vinylidene chloride) and will preferably only partially dissolve the surface of the poly(ethylene oxide) to improve the quality of the resulting adhesion. When the wad is immersed or tumbled in this solution and then removed and dried, it becomes fully coated with an outer layer of poly(vinylidene chloride) rendering the wad entirely insoluble in water.

An alternate method of making a poly(ethylene oxide) wad water insoluble is to expose it to an aqueous solution of poly(acrylic acid), as by spraying the surface or immersing the wad. An association reaction causes a complex to be formed on the surface in a manner which will be readily understood by those skilled in the art. This resulting association compound is insoluble in water and thus fully protects the wad in the shotshell.

If desired, other materials such as certain silicones may be used to react with the ethylene oxide polymer to produce insoluble coatings in a manner which will be readily understood by those skilled in the art. Further, gaseous compounds might be used to react with the poly(ethylene oxide). Such compounds could be utilized after most of the handling to which the wad must be subjected prior to loading has been completed. In fact, if desired, the reaction might be caused to occur within the shotshell after insertion of the wad so that the problem of surface abrasion during loading would be entirely alleviated.

lf surface abrasion during loading is expected, the wad may be rendered self healing. If, for example, the insoluble layer has been formed on the wad by reacting it with poly(acrylic acid), the surface of the wad may be coated with additional poly(acrylic acid). Should water be introduced into the shotshell, it will dissolve the poly(acrylic acid). The resulting aqueous solution of poly(acrylic acid), upon reaching an uncoated portion of the wad, will react therewith renewing the water-insoluble coating.

When a shotshell having a wad formed in accordance with this invention is fired, the water-insoluble surface is exposed to high temperatures caused by the burning propellant charge and significant surface abrasion due to interaction with the shot particles, barrel and choke so that a high percentage, if not all, of the waterinsoluble coating will be destroyed or removed, exposing the water-soluble material. Upon exposure to water, either due to immersion in a lake or pond or by subsequent rainfall at the location of the wad, the wad will quickly dissolve thus preventing a potential unsightly ecological problem.

I claim:

1. A method of manufacturing a shotshell wad, said method comprising the steps of forming a shotshell wad from water-soluble material and forming a waterinsoluble layer on said shotshell wad.

2. A method of manufacturing a shotshell was as in claim 1 wherein said shotshell wad is coated with a water-i'n-soluble material to form said water-insoluble layer.

3. A method of manufacturing a shotshell was as in claim 1 wherein said shotshell wad is exposed to a reactive material to chemically form said water-insoluble layer thereon.

4. A method of manufacturing a shotshell wad, said method comprising the steps of forming a shotshell wad from an ethylene oxide polymer and forming a waterinsoluble layer on said shotshell wad.

5. A method of manufacturing a shotshell wad as in claim 4 wherein said wad is immersed in a solution of poly(acrylic acid) to form said water-insoluble layer.

6. A method of manufacturing a shotshell wad as in claim 5 including the additional step of coating said insoluble layer with additional poly(acrylic acid).

7. A method of manufacturing a shotshell wad as in claim 4 wherein said wad is sprayed with a solution of poly(acrylic acid) to form said water-insoluble layer.

8. A method of manufacturing a shotshell wad as in claim 7 including the additional step of coating said insoluble layer with additional poly(acrylic acid).

9. A shotshell wad comprising a central portion of water-soluble material and a water-insoluble layer surrounding a central portion.

10. A shotshell wad as in claim 9 wherein said waterinsoluble layer comprises poly(vinylidene chloride).

11. A shotshell wad as in claim 9 wherein said watersoluble material comprises an ethylene oxide polymer.

12. A shotshell wad as in claim 11 wherein said water-insoluble layer comprises an association compound of poly(ethylene oxide) and poly(acrylic acid).

13. A shotshell wad as in claim 9 wherein said watersoluble material comprises a blend of poly(ethylene oxide) and urea.

14. A shotshell wad comprising a central portion of water-soluble material and a protective layer surrounding said central portion.

15. A shotshell wad as in claim 14 wherein said water-soluble material is an ethylene oxide polymer and said protective layer comprises poly( acrylic acid). 

2. A method of manufacturing a shotshell was as in claim 1 wherein said shotshell wad is coated with a water-in-soluble material to form said water-insoluble layer.
 3. A method of manufacturing a shotshell was as in claim 1 wherein said shotshell wad is exposed to a reactive material to chemically form said water-insoluble layer thereon.
 4. A method of manufacturing a shotshell wad, said method comprising the steps of forming a shotshell wad from an ethylene oxide polymer and forming a water-insoluble layer on said shotshell wad.
 5. A method of manufacturing a shotshell wad as in claim 4 wherein said wad is immersed in a solution of poly(acrylic acid) to form said water-insoluble layer.
 6. A method of manufacturing a shotshell wad as in claim 5 including the additional step of coating said insoluble layer with additional poly(acrylic acid).
 7. A method of manufacturing a shotshell wad as in claim 4 wherein said wad is sprayed with a solution of poly(acrylic acid) to form said water-insoluble layer.
 8. A method of manufacturing a shotshell wad as in claim 7 including the additional step of coating said insoluble layer with additional poly(acrylic acid).
 9. A shotshell wad comprising a central portion of water-soluble material and a water-insoluble layer surrounding a central portion.
 10. A shotshell wad as in claim 9 wherein said water-insoluble layer comprises poly(vinylidene chloride).
 11. A shotshell wad as in claim 9 wherein said water-soluble material comprises an ethylene oxide polymer.
 12. A shotshell wad as in claim 11 wherein said water-insoluble layer comprises an association compound of poly(ethylene oxide) and poly(acrylic acid).
 13. A shotshell wad as in claim 9 wherein said water-soluble material comprises a blend of poly(ethylene oxide) and urea.
 14. A shotshell wad comprising a central portion of water-soluble material and a protective layer surrounding said central portion.
 15. A shotshell wad as in claim 14 wherein said water-soluble material is an ethylene oxide polymer and said protective layer comprises poly(acrylic acid). 